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<head><meta charset="utf-8"><title>weekly meeting 2019-02-25 · wg-traits · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/index.html">wg-traits</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html">weekly meeting 2019-02-25</a></h3>

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<a name="159362539"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159362539" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159362539">(Feb 25 2019 at 19:01)</a>:</h4>
<p>Hi <span class="user-group-mention" data-user-group-id="692">@WG-compiler-traits</span> -- it's our regular monday triage.</p>



<a name="159362655"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159362655" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159362655">(Feb 25 2019 at 19:02)</a>:</h4>
<p>A few of us got together earlier today to try and make progress towards planning out a roadmap. I'm uploading the video now, but you can also check out <a href="https://paper.dropbox.com/doc/Traits-Roadmap-sketch--AYTQPvAVQ~p4lyElpr24zoAQAg-m6hucUslp7GihsY3SjNN2#:uid=036439056383521838336543&amp;h2=Buckets-by-time" target="_blank" title="https://paper.dropbox.com/doc/Traits-Roadmap-sketch--AYTQPvAVQ~p4lyElpr24zoAQAg-m6hucUslp7GihsY3SjNN2#:uid=036439056383521838336543&amp;h2=Buckets-by-time">the paper doc</a></p>



<a name="159362680"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159362680" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159362680">(Feb 25 2019 at 19:03)</a>:</h4>
<p>we didn't quite get as far as a specific proposal but I think we made a lot of progress, I was just trying to drill a bit more</p>



<a name="159362686"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159362686" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159362686">(Feb 25 2019 at 19:03)</a>:</h4>
<p>btw, I've created a <a href="https://paper.dropbox.com/folder/show/WG-Traits-e.1gg8YzoPEhbTkrhvQwJ2zzxYHlS9gAp3lY9aDouiA57dhPz04rrf" target="_blank" title="https://paper.dropbox.com/folder/show/WG-Traits-e.1gg8YzoPEhbTkrhvQwJ2zzxYHlS9gAp3lY9aDouiA57dhPz04rrf">WG-Traits directory in Paper</a></p>



<a name="159362704"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159362704" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159362704">(Feb 25 2019 at 19:03)</a>:</h4>
<p>and I think I'm tempted to use this as a "home" planning documents and things, instead of a dedicated GH repo</p>



<a name="159362764"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159362764" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159362764">(Feb 25 2019 at 19:04)</a>:</h4>
<p>I can add anyone who asks to the "Rust team" group</p>



<a name="159362770"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159362770" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159362770">(Feb 25 2019 at 19:04)</a>:</h4>
<p>which should give you some permissions</p>



<a name="159362849"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159362849" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159362849">(Feb 25 2019 at 19:05)</a>:</h4>
<p>I was just starting to try and distill the info from that paper into a series of specific proposals but I didn't <em>quite</em> get that far</p>



<a name="159362863"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159362863" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159362863">(Feb 25 2019 at 19:05)</a>:</h4>
<p>though I did e.g. <a href="https://paper.dropbox.com/doc/Traits-Roadmap-sketch--AYTQPvAVQ~p4lyElpr24zoAQAg-m6hucUslp7GihsY3SjNN2#:uid=493539681839934101758531&amp;h2=Possible-plan-for-upcoming-nex" target="_blank" title="https://paper.dropbox.com/doc/Traits-Roadmap-sketch--AYTQPvAVQ~p4lyElpr24zoAQAg-m6hucUslp7GihsY3SjNN2#:uid=493539681839934101758531&amp;h2=Possible-plan-for-upcoming-nex">write up some notes about GATs</a></p>



<a name="159362864"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159362864" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Sunjay Varma <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159362864">(Feb 25 2019 at 19:05)</a>:</h4>
<p>Requested access to the folder</p>



<a name="159362928"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159362928" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159362928">(Feb 25 2019 at 19:06)</a>:</h4>
<p><span class="user-mention" data-user-id="117350">@Sunjay Varma</span> I invited you to join the Rust group</p>



<a name="159362952"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159362952" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159362952">(Feb 25 2019 at 19:06)</a>:</h4>
<p>maybe it's worth talking about the GATs example just a bit</p>



<a name="159362965"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159362965" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159362965">(Feb 25 2019 at 19:06)</a>:</h4>
<p>cause I'm curious to get feedback from folks about it</p>



<a name="159362996"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159362996" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159362996">(Feb 25 2019 at 19:07)</a>:</h4>
<p>obviously, this is something that chalk handles with aplomb, but I also think it's something we can integrate fairly easily into rustc, at least at some level</p>



<a name="159363027"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363027" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363027">(Feb 25 2019 at 19:07)</a>:</h4>
<p>(I’m semi-afk) when can we « revisit the existing rules » for implied bounds? (Also what does that mean at all: do like some kind of recorded session on how they currently work and the open questions if any?)</p>



<a name="159363038"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363038" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363038">(Feb 25 2019 at 19:07)</a>:</h4>
<p>and -- thinking back on the NLL experience etc -- I think we should expect that integrating chalk in a "shippable" state will take some time. I could easily see it taking a year.</p>



<a name="159363093"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363093" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363093">(Feb 25 2019 at 19:08)</a>:</h4>
<p>(I could also see it being much faster, but there are a lot of unknowns, and it's a foundation part of the compiler)</p>



<a name="159363153"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363153" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363153">(Feb 25 2019 at 19:08)</a>:</h4>
<blockquote>
<p>(I’m semi-afk) when can we « revisit the existing rules » for implied bounds? (Also what does that mean at all: do like some kind of recorded session on how they currently work and the open questions if any?)</p>
</blockquote>
<p>good question. I think the process I imagined <span class="user-mention" data-user-id="131694">@scalexm</span> was yes a recorded session where we dig into the rules and try to spread knowledge around, and then translating that into edits to existing write-ups which form a kind of "spec"</p>



<a name="159363176"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363176" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363176">(Feb 25 2019 at 19:09)</a>:</h4>
<p>perhaps also exploring some of the variants proposed (e.g., limiting across crates and stuff)</p>



<a name="159363336"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363336" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363336">(Feb 25 2019 at 19:10)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> sounds good</p>



<a name="159363380"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363380" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363380">(Feb 25 2019 at 19:11)</a>:</h4>
<p>anyway, so back to GATs</p>



<a name="159363391"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363391" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363391">(Feb 25 2019 at 19:12)</a>:</h4>
<p>the thing I was thinking is that if we were to try and stand up an implementation on rustc as it is now</p>



<a name="159363473"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363473" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363473">(Feb 25 2019 at 19:12)</a>:</h4>
<p>I could imagine pursuing this by writing up some mentoring instructions, but it seems like something where we would like to recruit somebody to work on it -- or, maybe, even 2 people who could collaborate a bit.</p>



<a name="159363584"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363584" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363584">(Feb 25 2019 at 19:14)</a>:</h4>
<p>anyway, maybe that's too far into the weeds. But I'm basically trying to puzzle out how to "run" this effort best</p>



<a name="159363603"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363603" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Turon <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363603">(Feb 25 2019 at 19:14)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> to clarify,  are we hoping to come out of this meeting with some rough set of "assignments" of people to tasks? or not yet to that stage?</p>



<a name="159363637"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363637" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363637">(Feb 25 2019 at 19:15)</a>:</h4>
<blockquote>
<p>A few of us got together earlier today to try and make progress towards planning out a roadmap. I'm uploading the video now, but you can also check out <a href="https://paper.dropbox.com/doc/Traits-Roadmap-sketch--AYTQPvAVQ~p4lyElpr24zoAQAg-m6hucUslp7GihsY3SjNN2#:uid=036439056383521838336543&amp;h2=Buckets-by-time" target="_blank" title="https://paper.dropbox.com/doc/Traits-Roadmap-sketch--AYTQPvAVQ~p4lyElpr24zoAQAg-m6hucUslp7GihsY3SjNN2#:uid=036439056383521838336543&amp;h2=Buckets-by-time">the paper doc</a></p>
</blockquote>
<p>actually, maybe I should also explain what the structure was here. We basically grouped things into the "kind" of work required, and then tried to pick one or two items from each one that seemed like the most promising for pursuing immediately.</p>



<a name="159363676"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363676" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363676">(Feb 25 2019 at 19:15)</a>:</h4>
<blockquote>
<p><span class="user-mention silent" data-user-id="116009">nikomatsakis</span> to clarify,  are we hoping to come out of this meeting with some rough set of "assignments" of people to tasks? or not yet to that stage?</p>
</blockquote>
<p>I feel like we probably won't get <em>quite</em> that far</p>



<a name="159363683"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363683" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363683">(Feb 25 2019 at 19:15)</a>:</h4>
<p>but maybe :)</p>



<a name="159363775"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363775" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363775">(Feb 25 2019 at 19:17)</a>:</h4>
<p>sorry, pondering what Iwant to type :)</p>



<a name="159363818"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363818" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363818">(Feb 25 2019 at 19:17)</a>:</h4>
<p>I think that what I would say is: I feel like we shouldn't try to plan everything all at once, and that I'd kind of like to pick one or two items of various kinds to start focusing on and trying to see what org structure we think works</p>



<a name="159363906"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363906" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363906">(Feb 25 2019 at 19:18)</a>:</h4>
<p>(Personally I think I have too little time to try to pursue something else in addition to my ongoing work on chalk/design :/)</p>



<a name="159363912"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159363912" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159363912">(Feb 25 2019 at 19:18)</a>:</h4>
<p>I feel like GATs are a good item for "improving rustc as it is today", and also maybe an opportunity to do some teaching moments explaining <em>how</em> rustc works today</p>



<a name="159364052"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159364052" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159364052">(Feb 25 2019 at 19:20)</a>:</h4>
<p><span class="user-mention" data-user-id="131694">@scalexm</span> yeah, so I wouldn't expect any one person to do all the things =) </p>
<p>One of my question marks is just <em>what</em> to pursue when it comes to chalk. I feel like ideally we'd continue to pursue and improve chalk in parallel.</p>



<a name="159364061"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159364061" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159364061">(Feb 25 2019 at 19:20)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span>  to what extent can we do GATs in rustc today? e.g. can we do <code>type Foo&lt;T&gt;;</code> or would we be limited to lifetimes or...?</p>



<a name="159364123"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159364123" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159364123">(Feb 25 2019 at 19:21)</a>:</h4>
<p>I think we can do both, but we might have limitations around bounds</p>



<a name="159364213"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159364213" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159364213">(Feb 25 2019 at 19:22)</a>:</h4>
<p>seems reasonable</p>



<a name="159364245"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159364245" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159364245">(Feb 25 2019 at 19:23)</a>:</h4>
<p>I guess a reasonable question to ask is how useful that would be</p>



<a name="159364252"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159364252" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159364252">(Feb 25 2019 at 19:23)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> pursuing both in parallel seems like a good thing to do yes, so that we can eventually deliver features before the chalk integration is actually complete, while still being able to prototype everything in chalk as usual</p>



<a name="159364287"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159364287" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159364287">(Feb 25 2019 at 19:23)</a>:</h4>
<p>Moreover starting to implement GATs in rustc will probably make it more straightforward to have them handled by the chalk trait solver</p>



<a name="159364353"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159364353" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159364353">(Feb 25 2019 at 19:24)</a>:</h4>
<p>Yeah. So thinking more about this, I think what I want to have is an idea of the "tracks" of development</p>



<a name="159364398"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159364398" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159364398">(Feb 25 2019 at 19:25)</a>:</h4>
<p>I think I propose roughly 2:</p>
<ul>
<li>Improving rustc as it is today</li>
<li>Chalk and chalk integration (maybe also with rust-analyzer)</li>
</ul>
<p>but maybe that last one can be split up, or maybe there's a 3rd:</p>
<ul>
<li>Lang design-y things ;)</li>
</ul>



<a name="159364650"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159364650" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159364650">(Feb 25 2019 at 19:28)</a>:</h4>
<p>the "possible next steps" list we had in the document was kind of like this:</p>
<ul>
<li>HRTBs + Generic Closure --&gt; some mix of lowering to chalk predicates / syntax exploration / etc?</li>
<li>Specialization --&gt; at this stage I think mostly conceptual work around how to lower to chalk predicates</li>
<li>Named existential types --&gt; reviewing and trying to describe impl precisely</li>
<li>Handling region constraints in chalk? (also maybe intersects univeses) --&gt; digging into chalk solving strategy, interaction with polonius, etc</li>
<li>Clarify the lazy norm problem --&gt; explore what rustc does, come up with examples,</li>
<li>+Generic associated types  --&gt; can be done in rustc as we said</li>
<li>Existential lifetimes in impl Trait ---&gt; async-await overlap, need to dig into the problem and propose a plan</li>
<li>Chalk integration ---&gt; many different angles here :)</li>
</ul>



<a name="159364662"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159364662" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159364662">(Feb 25 2019 at 19:28)</a>:</h4>
<p>along with some notes of my own</p>



<a name="159364683"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159364683" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159364683">(Feb 25 2019 at 19:29)</a>:</h4>
<p>I feel like we are not yet at a state where we are ready to be like doing "widespread implementing"</p>



<a name="159364710"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159364710" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159364710">(Feb 25 2019 at 19:29)</a>:</h4>
<p>(i.e., writing up a bunch of mentored issues and putting out a call for folks to come and hack)</p>



<a name="159364724"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159364724" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159364724">(Feb 25 2019 at 19:29)</a>:</h4>
<p>not to say we can't write any code ;) I think e.g. <span class="user-mention" data-user-id="131694">@scalexm</span> and <span class="user-mention" data-user-id="124069">@Alexander Regueiro</span> have in-progress things that make sense to pursue</p>



<a name="159365005"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365005" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365005">(Feb 25 2019 at 19:33)</a>:</h4>
<p>I think a question mark for me is that I don't know who -- besides myself -- has time/appetite to try and "independently pursue" lines of inquiry. ;) I don't 100% know what it means, but I think it is "pick a topic that we think is key and drill into it to make an initial plan for what we will do". The nature of this plan depends a bit on the topic. I think <span class="user-mention" data-user-id="116010">@Aaron Turon</span> it might make sense for you to do some of that.</p>



<a name="159365025"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365025" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Turon <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365025">(Feb 25 2019 at 19:33)</a>:</h4>
<p>I agree,  though at least at first I'll need your help :)</p>



<a name="159365038"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365038" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365038">(Feb 25 2019 at 19:33)</a>:</h4>
<blockquote>
<p>Specialization --&gt; at this stage I think mostly conceptual work around how to lower to chalk predicates</p>
</blockquote>
<p>Is this taking <span class="user-mention" data-user-id="116010">@Aaron Turon</span>'s <code>specialize(T: Bound)</code> form and lowering? We'll need to think from lang POV on how to expose this to users also.</p>



<a name="159365051"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365051" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365051">(Feb 25 2019 at 19:33)</a>:</h4>
<p>Yes, I think there's some of both there</p>



<a name="159365054"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365054" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365054">(Feb 25 2019 at 19:34)</a>:</h4>
<p>Well, Aaron floated a syntax which we can use at least temporarily?</p>



<a name="159365118"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365118" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365118">(Feb 25 2019 at 19:34)</a>:</h4>
<p>I think for specialization maybe a very first step is actually trying to sketch out the "steps" like so -- kind of, what "kind" of spec do we want to support first, and then do the work of trying to make a chalk version of it, and then consider extensions</p>



<a name="159365137"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365137" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365137">(Feb 25 2019 at 19:35)</a>:</h4>
<p>And <span class="user-mention" data-user-id="116010">@Aaron Turon</span> I've been thinking it's a natural choice for you</p>



<a name="159365146"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365146" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365146">(Feb 25 2019 at 19:35)</a>:</h4>
<p>Though I'm definitely happy to follow along ;)</p>



<a name="159365158"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365158" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365158">(Feb 25 2019 at 19:35)</a>:</h4>
<p>my one doubt is, is it a good choice priority wise? :)</p>



<a name="159365171"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365171" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365171">(Feb 25 2019 at 19:35)</a>:</h4>
<p><span class="user-mention" data-user-id="116010">@Aaron Turon</span> aren't you working on GATs tho?</p>



<a name="159365173"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365173" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Turon <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365173">(Feb 25 2019 at 19:35)</a>:</h4>
<p>so it seems like probably the right immediate step is for some group of "subproject leads" to start fleshing out plans for individual projects, and then we can figure out a resource allocation?</p>



<a name="159365176"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365176" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365176">(Feb 25 2019 at 19:35)</a>:</h4>
<p>though I continue to feel specialization is pretty important, but I'm not sure on what basis I am making that judgement</p>



<a name="159365240"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365240" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365240">(Feb 25 2019 at 19:36)</a>:</h4>
<blockquote>
<p>so it seems like probably the right immediate step is for some group of "subproject leads" to start fleshing out plans for individual projects, and then we can figure out a resource allocation?</p>
</blockquote>
<p>yeah and I think it's ok if we don't have a lot right now</p>



<a name="159365251"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365251" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365251">(Feb 25 2019 at 19:36)</a>:</h4>
<p>i.e., because we are still sort of working out what it means</p>



<a name="159365252"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365252" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Turon <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365252">(Feb 25 2019 at 19:36)</a>:</h4>
<p>agreed, starting small/focused seems wise</p>



<a name="159365286"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365286" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Turon <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365286">(Feb 25 2019 at 19:37)</a>:</h4>
<p>and that comes back around,  i think, to GATs + Chalk being the "obvious" first targets?</p>



<a name="159365295"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365295" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365295">(Feb 25 2019 at 19:37)</a>:</h4>
<p>so I think I would like to try and drill into two distinct things this week:</p>
<ul>
<li>the async-await / "existential impl trait lifetime issues"</li>
<li>GATs or lazy norm</li>
</ul>



<a name="159365320"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365320" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365320">(Feb 25 2019 at 19:37)</a>:</h4>
<p>yep, so I think chalk is sort of a wild card in that I think we need to think what we mean when we say chalk</p>



<a name="159365384"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365384" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365384">(Feb 25 2019 at 19:38)</a>:</h4>
<p>relative to GATs I think it's less of a hard wall that libs authors hit?</p>
<p>I do like the fact that Aaron's surface syntax <code>specialize(T: Bound)</code> is clearly delineated cause it makes it more evident where many sources of non-parametricity arise from <span aria-label="slight smile" class="emoji emoji-1f642" role="img" title="slight smile">:slight_smile:</span></p>



<a name="159365401"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365401" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365401">(Feb 25 2019 at 19:38)</a>:</h4>
<p>(the first bullet item on my list is sort of intersecting with the async-await WG I think we need to start, but I think it ovelaps with this group, and <span class="user-mention" data-user-id="124069">@Alexander Regueiro</span> and I in particular had tlaked about working on it)</p>



<a name="159365443"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365443" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365443">(Feb 25 2019 at 19:39)</a>:</h4>
<p>well, so, it's maybe worth asking ourselves: I keep hearing GATs are important, but I feel like I odn't know exactly what people want them <em>for</em></p>



<a name="159365453"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365453" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365453">(Feb 25 2019 at 19:39)</a>:</h4>
<p>I mean I know reasons I've wanted them</p>



<a name="159365465"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365465" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365465">(Feb 25 2019 at 19:39)</a>:</h4>
<p>but in terms of (e.g.) blocking async-await work etc</p>



<a name="159365474"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365474" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365474">(Feb 25 2019 at 19:39)</a>:</h4>
<p>it'd be nice to have specific programs we want to compile</p>



<a name="159365478"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365478" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365478">(Feb 25 2019 at 19:39)</a>:</h4>
<p>and maybe that's the inital work that is needed on GATs, actually</p>



<a name="159365481"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365481" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Turon <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365481">(Feb 25 2019 at 19:39)</a>:</h4>
<p>agreed. i can put together a list on the async side</p>



<a name="159365507"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365507" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365507">(Feb 25 2019 at 19:39)</a>:</h4>
<p>so <span class="user-mention" data-user-id="116010">@Aaron Turon</span> what if we actually nominate you to "project lead" the GATs work (I'll assist)</p>



<a name="159365555"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365555" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Turon <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365555">(Feb 25 2019 at 19:40)</a>:</h4>
<p>(NB some of the desired traits would require bounds I believe)</p>



<a name="159365557"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365557" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365557">(Feb 25 2019 at 19:40)</a>:</h4>
<p>but in this phase it's not really about implementing</p>



<a name="159365571"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365571" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365571">(Feb 25 2019 at 19:40)</a>:</h4>
<p>and more about trying to decide how much impl is urgntly needed, to inform best path</p>



<a name="159365581"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365581" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365581">(Feb 25 2019 at 19:40)</a>:</h4>
<p>("this phase" hopefully not lasting very long :)</p>



<a name="159365582"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365582" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365582">(Feb 25 2019 at 19:40)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> StreamingIterators, making proptest's Strategy work for producing reference types, that sort of things.. Also abstracting over pointer types, etc.</p>



<a name="159365602"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365602" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Turon <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365602">(Feb 25 2019 at 19:40)</a>:</h4>
<blockquote>
<p>so <span class="user-mention silent" data-user-id="116010">Aaron Turon</span> what if we actually nominate you to "project lead" the GATs work (I'll assist)</p>
</blockquote>
<p>that sounds good to me. (on a personal note I'd also like to find some way to be involved with Chalk, but not necessarily in a "leading" way)</p>



<a name="159365604"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365604" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365604">(Feb 25 2019 at 19:40)</a>:</h4>
<p><span class="user-mention" data-user-id="126931">@centril</span> good list, let's make specific examples for each one</p>



<a name="159365628"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365628" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365628">(Feb 25 2019 at 19:41)</a>:</h4>
<p>so when it comes to chalk, what I think would be good is to maybe schedule a focused hour to talk out what it means and the plan there</p>



<a name="159365632"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365632" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365632">(Feb 25 2019 at 19:41)</a>:</h4>
<p>it feels like that is a whole meting on its own</p>



<a name="159365640"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365640" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365640">(Feb 25 2019 at 19:41)</a>:</h4>
<p><span class="user-mention" data-user-id="131694">@scalexm</span> do you think you'd be able to participate in such a thing?</p>



<a name="159365644"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365644" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365644">(Feb 25 2019 at 19:41)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> sure; in the paper doc or somewhere else?</p>



<a name="159365665"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365665" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365665">(Feb 25 2019 at 19:41)</a>:</h4>
<p><span class="user-mention" data-user-id="126931">@centril</span> work it out with <span class="user-mention" data-user-id="116010">@Aaron Turon</span> =)</p>



<a name="159365670"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365670" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365670">(Feb 25 2019 at 19:41)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> yes I think so</p>



<a name="159365746"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365746" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Turon <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365746">(Feb 25 2019 at 19:42)</a>:</h4>
<p>that would be really helpful; might also be good to recommend any specific background reading/code perusal</p>



<a name="159365780"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365780" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365780">(Feb 25 2019 at 19:43)</a>:</h4>
<p>ok so I see four things then:</p>
<ul>
<li>the async-await lifetime stuff</li>
<li>lazy normalization (Niko will try to do the same work <span class="user-mention" data-user-id="116010">@Aaron Turon</span> is doing: gather up exact examples and explore what goes wrong today)</li>
<li>GATs (specifically, gathering examples of programs we want to work so we can explore what it would take to make them work)</li>
<li>scheduling a chalk meeting  (and there should be some prep work there to frame the meeting, <span class="user-mention" data-user-id="116009">@nikomatsakis</span> can try to do some of that, maybe I'll ping you <span class="user-mention" data-user-id="131694">@scalexm</span> also?)</li>
</ul>



<a name="159365798"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365798" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365798">(Feb 25 2019 at 19:43)</a>:</h4>
<p>this feels like a pretty full agenda for this week if we can pull it off :)</p>



<a name="159365816"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365816" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365816">(Feb 25 2019 at 19:43)</a>:</h4>
<p>yay team</p>



<a name="159365826"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365826" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Turon <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365826">(Feb 25 2019 at 19:43)</a>:</h4>
<p>this  sounds great <span class="user-mention" data-user-id="116009">@nikomatsakis</span>!</p>



<a name="159365898"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365898" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365898">(Feb 25 2019 at 19:44)</a>:</h4>
<p>(As aforementioned, my tasks for the week is the <code>trait Foo = impl Bar;</code> FCP + tests for <span class="user-mention" data-user-id="124069">@Alexander Regueiro</span> )</p>



<a name="159365909"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365909" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365909">(Feb 25 2019 at 19:44)</a>:</h4>
<p>PS, I'm going to get back to the habit of trying to write a quick summary on internals after meetings</p>



<a name="159365912"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365912" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365912">(Feb 25 2019 at 19:44)</a>:</h4>
<p>so I'm going to go do that now</p>



<a name="159365935"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365935" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Aaron Turon <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365935">(Feb 25 2019 at 19:45)</a>:</h4>
<blockquote>
<p>PS, I'm going to get back to the habit of trying to write a quick summary on internals after meetings</p>
</blockquote>
<p>don't forget you can  always assign somebody to be the week's scribe &lt;3</p>



<a name="159365941"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365941" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365941">(Feb 25 2019 at 19:45)</a>:</h4>
<p>And thanks to all for participating, this is exactly what I hoped we'd achieve. <span aria-label="tada" class="emoji emoji-1f389" role="img" title="tada">:tada:</span></p>



<a name="159365947"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365947" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365947">(Feb 25 2019 at 19:45)</a>:</h4>
<p>ha, true</p>



<a name="159365950"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159365950" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159365950">(Feb 25 2019 at 19:45)</a>:</h4>
<blockquote>
<p>I mean I know reasons I've wanted them</p>
</blockquote>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span>  cool, send them our way :P</p>



<a name="159366116"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159366116" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159366116">(Feb 25 2019 at 19:46)</a>:</h4>
<blockquote>
<p>don't forget you can  always assign somebody to be the week's scribe &lt;3</p>
</blockquote>
<p>I'll scribe this time, but I like the idea of trying to make this a rotating duty</p>



<a name="159366127"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159366127" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159366127">(Feb 25 2019 at 19:47)</a>:</h4>
<p>/me notes that down for the future</p>



<a name="159367575"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159367575" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159367575">(Feb 25 2019 at 20:05)</a>:</h4>
<p>OK I wrote some notes here:</p>
<p><a href="https://github.com/rust-lang/compiler-team/pull/9" target="_blank" title="https://github.com/rust-lang/compiler-team/pull/9">https://github.com/rust-lang/compiler-team/pull/9</a></p>
<p>Please feel free to make any suggestions if there are important points I missed.</p>



<a name="159367599"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159367599" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159367599">(Feb 25 2019 at 20:05)</a>:</h4>
<p>Also, <span class="user-mention" data-user-id="126931">@centril</span>, I actually wasn't sure what to write about this:</p>
<blockquote>
<p>my tasks for the week is the trait Foo = impl Bar; FCP + tests for <span class="user-mention silent" data-user-id="124069">Alexander Regueiro</span> </p>
</blockquote>
<p>for one thing, I don't know what <code>trait Foo = impl Bar</code> is =)</p>



<a name="159367606"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159367606" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159367606">(Feb 25 2019 at 20:05)</a>:</h4>
<p>I think maybe you mean <code>Iterator&lt;Item: Bar&gt;</code>?</p>



<a name="159367658"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159367658" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159367658">(Feb 25 2019 at 20:06)</a>:</h4>
<p><span class="user-mention" data-user-id="116009">@nikomatsakis</span> oops, typo; I meant <code>type Foo = impl Bar;</code></p>



<a name="159367673"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159367673" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159367673">(Feb 25 2019 at 20:06)</a>:</h4>
<p>Ah, ok</p>



<a name="159367683"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159367683" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159367683">(Feb 25 2019 at 20:06)</a>:</h4>
<p>I was going to say "woah that is a new feature indeed!"</p>



<a name="159367692"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159367692" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> centril <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159367692">(Feb 25 2019 at 20:06)</a>:</h4>
<p>:P</p>



<a name="159371718"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159371718" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> varkor <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159371718">(Feb 25 2019 at 21:04)</a>:</h4>
<p>I haven't been keeping wg-traits on my radar recently, but I'm planning to switch my focus here once the (rustc side of) const generics work is done (or at least, merged and without too many outstanding issues)</p>



<a name="159371767"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159371767" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> varkor <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159371767">(Feb 25 2019 at 21:05)</a>:</h4>
<p>things are progressing in that area too, so hopefully I'll be able to lend a helping hand to whatever work here is the highest priority soon :)</p>



<a name="159372533"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159372533" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Alexander Regueiro <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159372533">(Feb 25 2019 at 21:14)</a>:</h4>
<p><span class="user-mention" data-user-id="121053">@varkor</span> good stuff! what's the non-rustc side of const generics?</p>



<a name="159453316"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159453316" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> varkor <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159453316">(Feb 26 2019 at 20:02)</a>:</h4>
<p>const generics in chalk, for one</p>



<a name="159940895"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159940895" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159940895">(Mar 04 2019 at 19:12)</a>:</h4>
<p>(deleted)</p>



<a name="159940919"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/weekly%20meeting%202019-02-25/near/159940919" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> scalexm <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/weekly.20meeting.202019-02-25.html#159940919">(Mar 04 2019 at 19:13)</a>:</h4>
<p>(deleted)</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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